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Truck-tire testing proposal toughens standards

The National Highway Traffic Safety Administration (NHTSA) has proposed new truck tire testing procedures for nearly 98% of all commercial tires sold in the U.S. Fleets, though, may see only minimal impact on the cost of their tires should the rule go into effect

The National Highway Traffic Safety Administration (NHTSA) has proposed new truck tire testing procedures for nearly 98% of all commercial tires sold in the U.S. Fleets, though, may see only minimal impact on the cost of their tires should the rule go into effect.

Under the Notice of Proposed Rulemaking (NPRM), which was published in the Federal Register last week, new endurance and speed-testing of commercial tires would modernize the current testing system, which has been in place since 1973, NHTSA said. The proposal, an update to the TREAD Act, would also require sidewalls to include the tire’s maximum speed rating.

“Michelin is very pleased to finally see the Notice of Proposed Rulemaking for the TREAD Act mandated update of FMVSS119, the Federal Motor Vehicle Safety Standard for commercial truck and bus tires,” Mike Wischhusen, director, industry standards & government regulations for Michelin North America told Fleet Owner. “We, along with the rest of the industry, have been working with the Rubber Manufacturers Assn. over the last several years to share tire performance data and tire testing expertise with NHTSA.”

The NPRM is in response to the massive recall of Firestone consumer tires back in 2000. That recall was prompted by a federal investigation of complaints that rubber peeled off the tire casings. More than 6.5 million tires were eventually recalled.

While commercial tires were never part of the recall or investigation, Congress mandated that NHTSA update its testing protocols for all tires sold in the U.S. This rule addresses the commercial aspects of that Congressional mandate.

The proposed rule would toughen the endurance test and add a new high-speed test for new radial tires in load range F, G, H, J and L, which the agency believes make up 98% of the commercial market. These rules would apply for non-speed restrictive tires. NHTSA is also considering placing non-speed restricted, load-range M radial tires under the same criteria.

The NPRM is open for public comment until Nov. 29, 2010. But the proposal is unlikely to have much impact on the fleets who purchase tires, but tire manufacturers will have to adjust, said Guy Walenga, director of engineering-commercial products & technology for Bridgestone Bandag Tire Solutions (BBTS).

“That endurance test is tougher,” Walenga told Fleet Owner. “It’s done at higher loads, and even though it will be at the same 47-hour [test time], it will be at a much higher speed.”

NHTSA is proposing to raise the current endurance test speed to 50 mpg for all load ranges. Currently, there are varying test speeds based on the load range of the tire. Also, test inflation pressure would be set at 80% of the sidewall-labeled inflation pressure that corresponds to the tire’s maximum load rating. This is a 20% decrease from the current test which requires tires to be fully inflated.

The biggest change will be the addition of the high-speed testing. Currently, FMVSS119 does not require this type of test.

The speed testing would begin after a two-hour “break-in” period for the tire at 50 mph with 85% of maximum load rating and inflation pressure set at 90% of maximum. Manufacturers would have to test the tires for 90 min. broken into three 30-min. “speed steps.”

The first step would test the tire at 12 mph less than maximum speed; the second at 6 mpg less than maximum speed; and the final test would occur at maximum speed. Test loads would be set at 85% of maximum load rating for the tire with inflation pressure set at 90%.

Walenga said it was his understanding that NHTSA used off-the-shelf tires to test the proposed standard and only one of the tires tested did not pass. Walenga could not say whether all tires currently sold would pass as there are any number of specialty sizes on the market that probably have not been tested yet, he said.

Walenga added that Bridgestone, and other tire manufacturers, will be ready when and if the proposal goes into effect. “We don’t consider it minor, even though it appears most of our tires will meet the requirement,” he said.

Whether the new testing raises the end cost of tires is still too far off to consider at this time. When the new standards finally are approved, they may be different than what has just been proposed, Walenga said, and could still be several years away depending on how NHTSA chooses to implement the changes.

“We are currently working with RMA to develop comments on the NPRM that will be submitted to the NHTSA docket before the closure of the comment period on Nov. 29,” Michelin’s Wischhusen said. “Working together with the [NHTSA] we are confident that we can achieve an effective and efficient new safety standard that will improve the already very high safety levels on our highways without imposing undue and unnecessary hardships on the industry.”

A Goodyear spokesperson also sounded confident about their products meeting the standards, if adopted.

“Goodyear supports actions that make the roads safer for all drivers,” a Goodyear spokesman told Fleet Owner. “Though the proposed upgrades to commercial truck-tire standards are not final, we are confident that our products will continue to deliver a high level of performance in real-world conditions and comply with whatever rules may be adopted.”

In the end, fleets will have tires that they can trust, BBTS’s Walenga said.

“This should help because it really raises the bar you have to meet to earn the DOT standard,” he said.